VI. STUDIES ON ILEMOLYSINS. 1 



FOURTH COMMUNICATION. 

 By Professor Dr. P. EHRLICH and Dr. J. MORGENROTH. 



THE continued thorough study of both natural haemolysins and 

 those produced by injections of red blood-cells leads to the con- 

 ception of an extraordinary multiplicity of the substances which are 

 either normally present in serum or which we are able at will to 

 produce therein. That in the action of the artificially developed 

 hsemolysins two substances are always concerned may now be regarded 

 as a fact supported by numerous individual observations. The two 

 substances are: (1) the specific immune body produced by immuniza- 

 tion, and (2) a substance, usually thermolabile, contained even in nor- 

 mal serum, our " complement" and the "alexin" of Buchner and of 

 Bordet. We have shown that the erythrocytes anchor the immune 

 body in a specific manner, while they do not combine with the isolated 

 complement as such. The fact that the immune body has been 

 bound by the corresponding erythrocytes has been confirmed by 

 von Dungern, Bordet, and Buchner. Out of a fluid containing both 

 immune body and complement, at C. the blood-cells take up 

 only immune body, at higher temperatures both immune body and 

 complement. We were able to explain this phenomenon only by 

 assuming that the immune body possesses two haptophore groups, 

 one of greater affinity, which is related to a receptor of the blood- 

 cells and acts at C., the other, of less affinity, which combines 

 only at higher temperatures with a corresponding group of the com- 

 plement. 



Our views can be expressed most simply by means of the fol- 

 lowing rough diagram (see figure). This will also serve to show 

 the close relations existing between lysins and the true toxins. 



1 Reprint from the Berlin, klin. Wochenschrift, 1900, No. 31. 



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